Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.25 / gold / dwarf_reader.cc
1 // dwarf_reader.cc -- parse dwarf2/3 debug information
2
3 // Copyright (C) 2007-2014 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <algorithm>
26 #include <utility>
27 #include <vector>
28
29 #include "elfcpp_swap.h"
30 #include "dwarf.h"
31 #include "object.h"
32 #include "reloc.h"
33 #include "dwarf_reader.h"
34 #include "int_encoding.h"
35 #include "compressed_output.h"
36
37 namespace gold {
38
39 // Class Sized_elf_reloc_mapper
40
41 // Initialize the relocation tracker for section RELOC_SHNDX.
42
43 template<int size, bool big_endian>
44 bool
45 Sized_elf_reloc_mapper<size, big_endian>::do_initialize(
46     unsigned int reloc_shndx, unsigned int reloc_type)
47 {
48   this->reloc_type_ = reloc_type;
49   return this->track_relocs_.initialize(this->object_, reloc_shndx,
50                                         reloc_type);
51 }
52
53 // Looks in the symtab to see what section a symbol is in.
54
55 template<int size, bool big_endian>
56 unsigned int
57 Sized_elf_reloc_mapper<size, big_endian>::symbol_section(
58     unsigned int symndx, Address* value, bool* is_ordinary)
59 {
60   const int symsize = elfcpp::Elf_sizes<size>::sym_size;
61   gold_assert(static_cast<off_t>((symndx + 1) * symsize) <= this->symtab_size_);
62   elfcpp::Sym<size, big_endian> elfsym(this->symtab_ + symndx * symsize);
63   *value = elfsym.get_st_value();
64   return this->object_->adjust_sym_shndx(symndx, elfsym.get_st_shndx(),
65                                          is_ordinary);
66 }
67
68 // Return the section index and offset within the section of
69 // the target of the relocation for RELOC_OFFSET.
70
71 template<int size, bool big_endian>
72 unsigned int
73 Sized_elf_reloc_mapper<size, big_endian>::do_get_reloc_target(
74     off_t reloc_offset, off_t* target_offset)
75 {
76   this->track_relocs_.advance(reloc_offset);
77   if (reloc_offset != this->track_relocs_.next_offset())
78     return 0;
79   unsigned int symndx = this->track_relocs_.next_symndx();
80   typename elfcpp::Elf_types<size>::Elf_Addr value;
81   bool is_ordinary;
82   unsigned int target_shndx = this->symbol_section(symndx, &value,
83                                                    &is_ordinary);
84   if (!is_ordinary)
85     return 0;
86   if (this->reloc_type_ == elfcpp::SHT_RELA)
87     value += this->track_relocs_.next_addend();
88   *target_offset = value;
89   return target_shndx;
90 }
91
92 static inline Elf_reloc_mapper*
93 make_elf_reloc_mapper(Relobj* object, const unsigned char* symtab,
94                       off_t symtab_size)
95 {
96   if (object->elfsize() == 32)
97     {
98       if (object->is_big_endian())
99         {
100 #ifdef HAVE_TARGET_32_BIG
101           return new Sized_elf_reloc_mapper<32, true>(object, symtab,
102                                                       symtab_size);
103 #else
104           gold_unreachable();
105 #endif
106         }
107       else
108         {
109 #ifdef HAVE_TARGET_32_LITTLE
110           return new Sized_elf_reloc_mapper<32, false>(object, symtab,
111                                                        symtab_size);
112 #else
113           gold_unreachable();
114 #endif
115         }
116     }
117   else if (object->elfsize() == 64)
118     {
119       if (object->is_big_endian())
120         {
121 #ifdef HAVE_TARGET_64_BIG
122           return new Sized_elf_reloc_mapper<64, true>(object, symtab,
123                                                       symtab_size);
124 #else
125           gold_unreachable();
126 #endif
127         }
128       else
129         {
130 #ifdef HAVE_TARGET_64_LITTLE
131           return new Sized_elf_reloc_mapper<64, false>(object, symtab,
132                                                        symtab_size);
133 #else
134           gold_unreachable();
135 #endif
136         }
137     }
138   else
139     gold_unreachable();
140 }
141
142 // class Dwarf_abbrev_table
143
144 void
145 Dwarf_abbrev_table::clear_abbrev_codes()
146 {
147   for (unsigned int code = 0; code < this->low_abbrev_code_max_; ++code)
148     {
149       if (this->low_abbrev_codes_[code] != NULL)
150         {
151           delete this->low_abbrev_codes_[code];
152           this->low_abbrev_codes_[code] = NULL;
153         }
154     }
155   for (Abbrev_code_table::iterator it = this->high_abbrev_codes_.begin();
156        it != this->high_abbrev_codes_.end();
157        ++it)
158     {
159       if (it->second != NULL)
160         delete it->second;
161     }
162   this->high_abbrev_codes_.clear();
163 }
164
165 // Read the abbrev table from an object file.
166
167 bool
168 Dwarf_abbrev_table::do_read_abbrevs(
169     Relobj* object,
170     unsigned int abbrev_shndx,
171     off_t abbrev_offset)
172 {
173   this->clear_abbrev_codes();
174
175   // If we don't have relocations, abbrev_shndx will be 0, and
176   // we'll have to hunt for the .debug_abbrev section.
177   if (abbrev_shndx == 0 && this->abbrev_shndx_ > 0)
178     abbrev_shndx = this->abbrev_shndx_;
179   else if (abbrev_shndx == 0)
180     {
181       for (unsigned int i = 1; i < object->shnum(); ++i)
182         {
183           std::string name = object->section_name(i);
184           if (name == ".debug_abbrev" || name == ".zdebug_abbrev")
185             {
186               abbrev_shndx = i;
187               // Correct the offset.  For incremental update links, we have a
188               // relocated offset that is relative to the output section, but
189               // here we need an offset relative to the input section.
190               abbrev_offset -= object->output_section_offset(i);
191               break;
192             }
193         }
194       if (abbrev_shndx == 0)
195         return false;
196     }
197
198   // Get the section contents and decompress if necessary.
199   if (abbrev_shndx != this->abbrev_shndx_)
200     {
201       if (this->owns_buffer_ && this->buffer_ != NULL)
202         {
203           delete[] this->buffer_;
204           this->owns_buffer_ = false;
205         }
206
207       section_size_type buffer_size;
208       this->buffer_ =
209           object->decompressed_section_contents(abbrev_shndx,
210                                                 &buffer_size,
211                                                 &this->owns_buffer_);
212       this->buffer_end_ = this->buffer_ + buffer_size;
213       this->abbrev_shndx_ = abbrev_shndx;
214     }
215
216   this->buffer_pos_ = this->buffer_ + abbrev_offset;
217   return true;
218 }
219
220 // Lookup the abbrev code entry for CODE.  This function is called
221 // only when the abbrev code is not in the direct lookup table.
222 // It may be in the hash table, it may not have been read yet,
223 // or it may not exist in the abbrev table.
224
225 const Dwarf_abbrev_table::Abbrev_code*
226 Dwarf_abbrev_table::do_get_abbrev(unsigned int code)
227 {
228   // See if the abbrev code is already in the hash table.
229   Abbrev_code_table::const_iterator it = this->high_abbrev_codes_.find(code);
230   if (it != this->high_abbrev_codes_.end())
231     return it->second;
232
233   // Read and store abbrev code definitions until we find the
234   // one we're looking for.
235   for (;;)
236     {
237       // Read the abbrev code.  A zero here indicates the end of the
238       // abbrev table.
239       size_t len;
240       if (this->buffer_pos_ >= this->buffer_end_)
241         return NULL;
242       uint64_t nextcode = read_unsigned_LEB_128(this->buffer_pos_, &len);
243       if (nextcode == 0)
244         {
245           this->buffer_pos_ = this->buffer_end_;
246           return NULL;
247         }
248       this->buffer_pos_ += len;
249
250       // Read the tag.
251       if (this->buffer_pos_ >= this->buffer_end_)
252         return NULL;
253       uint64_t tag = read_unsigned_LEB_128(this->buffer_pos_, &len);
254       this->buffer_pos_ += len;
255
256       // Read the has_children flag.
257       if (this->buffer_pos_ >= this->buffer_end_)
258         return NULL;
259       bool has_children = *this->buffer_pos_ == elfcpp::DW_CHILDREN_yes;
260       this->buffer_pos_ += 1;
261
262       // Read the list of (attribute, form) pairs.
263       Abbrev_code* entry = new Abbrev_code(tag, has_children);
264       for (;;)
265         {
266           // Read the attribute.
267           if (this->buffer_pos_ >= this->buffer_end_)
268             return NULL;
269           uint64_t attr = read_unsigned_LEB_128(this->buffer_pos_, &len);
270           this->buffer_pos_ += len;
271
272           // Read the form.
273           if (this->buffer_pos_ >= this->buffer_end_)
274             return NULL;
275           uint64_t form = read_unsigned_LEB_128(this->buffer_pos_, &len);
276           this->buffer_pos_ += len;
277
278           // A (0,0) pair terminates the list.
279           if (attr == 0 && form == 0)
280             break;
281
282           if (attr == elfcpp::DW_AT_sibling)
283             entry->has_sibling_attribute = true;
284
285           entry->add_attribute(attr, form);
286         }
287
288       this->store_abbrev(nextcode, entry);
289       if (nextcode == code)
290         return entry;
291     }
292
293   return NULL;
294 }
295
296 // class Dwarf_ranges_table
297
298 // Read the ranges table from an object file.
299
300 bool
301 Dwarf_ranges_table::read_ranges_table(
302     Relobj* object,
303     const unsigned char* symtab,
304     off_t symtab_size,
305     unsigned int ranges_shndx)
306 {
307   // If we've already read this abbrev table, return immediately.
308   if (this->ranges_shndx_ > 0
309       && this->ranges_shndx_ == ranges_shndx)
310     return true;
311
312   // If we don't have relocations, ranges_shndx will be 0, and
313   // we'll have to hunt for the .debug_ranges section.
314   if (ranges_shndx == 0 && this->ranges_shndx_ > 0)
315     ranges_shndx = this->ranges_shndx_;
316   else if (ranges_shndx == 0)
317     {
318       for (unsigned int i = 1; i < object->shnum(); ++i)
319         {
320           std::string name = object->section_name(i);
321           if (name == ".debug_ranges" || name == ".zdebug_ranges")
322             {
323               ranges_shndx = i;
324               this->output_section_offset_ = object->output_section_offset(i);
325               break;
326             }
327         }
328       if (ranges_shndx == 0)
329         return false;
330     }
331
332   // Get the section contents and decompress if necessary.
333   if (ranges_shndx != this->ranges_shndx_)
334     {
335       if (this->owns_ranges_buffer_ && this->ranges_buffer_ != NULL)
336         {
337           delete[] this->ranges_buffer_;
338           this->owns_ranges_buffer_ = false;
339         }
340
341       section_size_type buffer_size;
342       this->ranges_buffer_ =
343           object->decompressed_section_contents(ranges_shndx,
344                                                 &buffer_size,
345                                                 &this->owns_ranges_buffer_);
346       this->ranges_buffer_end_ = this->ranges_buffer_ + buffer_size;
347       this->ranges_shndx_ = ranges_shndx;
348     }
349
350   if (this->ranges_reloc_mapper_ != NULL)
351     {
352       delete this->ranges_reloc_mapper_;
353       this->ranges_reloc_mapper_ = NULL;
354     }
355
356   // For incremental objects, we have no relocations.
357   if (object->is_incremental())
358     return true;
359
360   // Find the relocation section for ".debug_ranges".
361   unsigned int reloc_shndx = 0;
362   unsigned int reloc_type = 0;
363   for (unsigned int i = 0; i < object->shnum(); ++i)
364     {
365       reloc_type = object->section_type(i);
366       if ((reloc_type == elfcpp::SHT_REL
367            || reloc_type == elfcpp::SHT_RELA)
368           && object->section_info(i) == ranges_shndx)
369         {
370           reloc_shndx = i;
371           break;
372         }
373     }
374
375   this->ranges_reloc_mapper_ = make_elf_reloc_mapper(object, symtab,
376                                                      symtab_size);
377   this->ranges_reloc_mapper_->initialize(reloc_shndx, reloc_type);
378   this->reloc_type_ = reloc_type;
379
380   return true;
381 }
382
383 // Read a range list from section RANGES_SHNDX at offset RANGES_OFFSET.
384
385 Dwarf_range_list*
386 Dwarf_ranges_table::read_range_list(
387     Relobj* object,
388     const unsigned char* symtab,
389     off_t symtab_size,
390     unsigned int addr_size,
391     unsigned int ranges_shndx,
392     off_t offset)
393 {
394   Dwarf_range_list* ranges;
395
396   if (!this->read_ranges_table(object, symtab, symtab_size, ranges_shndx))
397     return NULL;
398
399   // Correct the offset.  For incremental update links, we have a
400   // relocated offset that is relative to the output section, but
401   // here we need an offset relative to the input section.
402   offset -= this->output_section_offset_;
403
404   // Read the range list at OFFSET.
405   ranges = new Dwarf_range_list();
406   off_t base = 0;
407   for (;
408        this->ranges_buffer_ + offset < this->ranges_buffer_end_;
409        offset += 2 * addr_size)
410     {
411       off_t start;
412       off_t end;
413
414       // Read the raw contents of the section.
415       if (addr_size == 4)
416         {
417           start = this->dwinfo_->read_from_pointer<32>(this->ranges_buffer_
418                                                        + offset);
419           end = this->dwinfo_->read_from_pointer<32>(this->ranges_buffer_
420                                                      + offset + 4);
421         }
422       else
423         {
424           start = this->dwinfo_->read_from_pointer<64>(this->ranges_buffer_
425                                                        + offset);
426           end = this->dwinfo_->read_from_pointer<64>(this->ranges_buffer_
427                                                      + offset + 8);
428         }
429
430       // Check for relocations and adjust the values.
431       unsigned int shndx1 = 0;
432       unsigned int shndx2 = 0;
433       if (this->ranges_reloc_mapper_ != NULL)
434         {
435           shndx1 = this->lookup_reloc(offset, &start);
436           shndx2 = this->lookup_reloc(offset + addr_size, &end);
437         }
438
439       // End of list is marked by a pair of zeroes.
440       if (shndx1 == 0 && start == 0 && end == 0)
441         break;
442
443       // A "base address selection entry" is identified by
444       // 0xffffffff for the first value of the pair.  The second
445       // value is used as a base for subsequent range list entries.
446       if (shndx1 == 0 && start == -1)
447         base = end;
448       else if (shndx1 == shndx2)
449         {
450           if (shndx1 == 0 || object->is_section_included(shndx1))
451             ranges->add(shndx1, base + start, base + end);
452         }
453       else
454         gold_warning(_("%s: DWARF info may be corrupt; offsets in a "
455                        "range list entry are in different sections"),
456                      object->name().c_str());
457     }
458
459   return ranges;
460 }
461
462 // Look for a relocation at offset OFF in the range table,
463 // and return the section index and offset of the target.
464
465 unsigned int
466 Dwarf_ranges_table::lookup_reloc(off_t off, off_t* target_off)
467 {
468   off_t value;
469   unsigned int shndx =
470       this->ranges_reloc_mapper_->get_reloc_target(off, &value);
471   if (shndx == 0)
472     return 0;
473   if (this->reloc_type_ == elfcpp::SHT_REL)
474     *target_off += value;
475   else
476     *target_off = value;
477   return shndx;
478 }
479
480 // class Dwarf_pubnames_table
481
482 // Read the pubnames section from the object file.
483
484 bool
485 Dwarf_pubnames_table::read_section(Relobj* object, const unsigned char* symtab,
486                                    off_t symtab_size)
487 {
488   section_size_type buffer_size;
489   unsigned int shndx = 0;
490   const char* name = this->is_pubtypes_ ? "pubtypes" : "pubnames";
491   const char* gnu_name = (this->is_pubtypes_
492                           ? "gnu_pubtypes"
493                           : "gnu_pubnames");
494
495   for (unsigned int i = 1; i < object->shnum(); ++i)
496     {
497       std::string section_name = object->section_name(i);
498       const char* section_name_suffix = section_name.c_str();
499       if (is_prefix_of(".debug_", section_name_suffix))
500         section_name_suffix += 7;
501       else if (is_prefix_of(".zdebug_", section_name_suffix))
502         section_name_suffix += 8;
503       else
504         continue;
505       if (strcmp(section_name_suffix, name) == 0)
506         {
507           shndx = i;
508           break;
509         }
510       else if (strcmp(section_name_suffix, gnu_name) == 0)
511         {
512           shndx = i;
513           this->is_gnu_style_ = true;
514           break;
515         }
516     }
517   if (shndx == 0)
518     return false;
519
520   this->buffer_ = object->decompressed_section_contents(shndx,
521                                                         &buffer_size,
522                                                         &this->owns_buffer_);
523   if (this->buffer_ == NULL)
524     return false;
525   this->buffer_end_ = this->buffer_ + buffer_size;
526
527   // For incremental objects, we have no relocations.
528   if (object->is_incremental())
529     return true;
530
531   // Find the relocation section
532   unsigned int reloc_shndx = 0;
533   unsigned int reloc_type = 0;
534   for (unsigned int i = 0; i < object->shnum(); ++i)
535     {
536       reloc_type = object->section_type(i);
537       if ((reloc_type == elfcpp::SHT_REL
538            || reloc_type == elfcpp::SHT_RELA)
539           && object->section_info(i) == shndx)
540         {
541           reloc_shndx = i;
542           break;
543         }
544     }
545
546   this->reloc_mapper_ = make_elf_reloc_mapper(object, symtab, symtab_size);
547   this->reloc_mapper_->initialize(reloc_shndx, reloc_type);
548   this->reloc_type_ = reloc_type;
549
550   return true;
551 }
552
553 // Read the header for the set at OFFSET.
554
555 bool
556 Dwarf_pubnames_table::read_header(off_t offset)
557 {
558   // Make sure we have actually read the section.
559   gold_assert(this->buffer_ != NULL);
560
561   if (offset < 0 || offset + 14 >= this->buffer_end_ - this->buffer_)
562     return false;
563
564   const unsigned char* pinfo = this->buffer_ + offset;
565
566   // Read the unit_length field.
567   uint64_t unit_length = this->dwinfo_->read_from_pointer<32>(pinfo);
568   pinfo += 4;
569   if (unit_length == 0xffffffff)
570     {
571       unit_length = this->dwinfo_->read_from_pointer<64>(pinfo);
572       this->unit_length_ = unit_length + 12;
573       pinfo += 8;
574       this->offset_size_ = 8;
575     }
576   else
577     {
578       this->unit_length_ = unit_length + 4;
579       this->offset_size_ = 4;
580     }
581   this->end_of_table_ = pinfo + unit_length;
582
583   // If unit_length is too big, maybe we should reject the whole table,
584   // but in cases we know about, it seems OK to assume that the table
585   // is valid through the actual end of the section.
586   if (this->end_of_table_ > this->buffer_end_)
587     this->end_of_table_ = this->buffer_end_;
588
589   // Check the version.
590   unsigned int version = this->dwinfo_->read_from_pointer<16>(pinfo);
591   pinfo += 2;
592   if (version != 2)
593     return false;
594
595   this->reloc_mapper_->get_reloc_target(pinfo - this->buffer_,
596                                         &this->cu_offset_);
597
598   // Skip the debug_info_offset and debug_info_size fields.
599   pinfo += 2 * this->offset_size_;
600
601   if (pinfo >= this->buffer_end_)
602     return false;
603
604   this->pinfo_ = pinfo;
605   return true;
606 }
607
608 // Read the next name from the set.
609
610 const char*
611 Dwarf_pubnames_table::next_name(uint8_t* flag_byte)
612 {
613   const unsigned char* pinfo = this->pinfo_;
614
615   // Check for end of list.  The table should be terminated by an
616   // entry containing nothing but a DIE offset of 0.
617   if (pinfo + this->offset_size_ >= this->end_of_table_)
618     return NULL;
619
620   // Skip the offset within the CU.  If this is zero, but we're not
621   // at the end of the table, then we have a real pubnames entry
622   // whose DIE offset is 0 (likely to be a GCC bug).  Since we
623   // don't actually use the DIE offset in building .gdb_index,
624   // it's harmless.
625   pinfo += this->offset_size_;
626
627   if (this->is_gnu_style_)
628     *flag_byte = *pinfo++;
629   else
630     *flag_byte = 0;
631
632   // Return a pointer to the string at the current location,
633   // and advance the pointer to the next entry.
634   const char* ret = reinterpret_cast<const char*>(pinfo);
635   while (pinfo < this->buffer_end_ && *pinfo != '\0')
636     ++pinfo;
637   if (pinfo < this->buffer_end_)
638     ++pinfo;
639
640   this->pinfo_ = pinfo;
641   return ret;
642 }
643
644 // class Dwarf_die
645
646 Dwarf_die::Dwarf_die(
647     Dwarf_info_reader* dwinfo,
648     off_t die_offset,
649     Dwarf_die* parent)
650   : dwinfo_(dwinfo), parent_(parent), die_offset_(die_offset),
651     child_offset_(0), sibling_offset_(0), abbrev_code_(NULL), attributes_(),
652     attributes_read_(false), name_(NULL), name_off_(-1), linkage_name_(NULL),
653     linkage_name_off_(-1), string_shndx_(0), specification_(0),
654     abstract_origin_(0)
655 {
656   size_t len;
657   const unsigned char* pdie = dwinfo->buffer_at_offset(die_offset);
658   if (pdie == NULL)
659     return;
660   unsigned int code = read_unsigned_LEB_128(pdie, &len);
661   if (code == 0)
662     {
663       if (parent != NULL)
664         parent->set_sibling_offset(die_offset + len);
665       return;
666     }
667   this->attr_offset_ = len;
668
669   // Lookup the abbrev code in the abbrev table.
670   this->abbrev_code_ = dwinfo->get_abbrev(code);
671 }
672
673 // Read all the attributes of the DIE.
674
675 bool
676 Dwarf_die::read_attributes()
677 {
678   if (this->attributes_read_)
679     return true;
680
681   gold_assert(this->abbrev_code_ != NULL);
682
683   const unsigned char* pdie =
684       this->dwinfo_->buffer_at_offset(this->die_offset_);
685   if (pdie == NULL)
686     return false;
687   const unsigned char* pattr = pdie + this->attr_offset_;
688
689   unsigned int nattr = this->abbrev_code_->attributes.size();
690   this->attributes_.reserve(nattr);
691   for (unsigned int i = 0; i < nattr; ++i)
692     {
693       size_t len;
694       unsigned int attr = this->abbrev_code_->attributes[i].attr;
695       unsigned int form = this->abbrev_code_->attributes[i].form;
696       if (form == elfcpp::DW_FORM_indirect)
697         {
698           form = read_unsigned_LEB_128(pattr, &len);
699           pattr += len;
700         }
701       off_t attr_off = this->die_offset_ + (pattr - pdie);
702       bool ref_form = false;
703       Attribute_value attr_value;
704       attr_value.attr = attr;
705       attr_value.form = form;
706       attr_value.aux.shndx = 0;
707       switch(form)
708         {
709           case elfcpp::DW_FORM_flag_present:
710             attr_value.val.intval = 1;
711             break;
712           case elfcpp::DW_FORM_strp:
713             {
714               off_t str_off;
715               if (this->dwinfo_->offset_size() == 4)
716                 str_off = this->dwinfo_->read_from_pointer<32>(&pattr);
717               else
718                 str_off = this->dwinfo_->read_from_pointer<64>(&pattr);
719               unsigned int shndx =
720                   this->dwinfo_->lookup_reloc(attr_off, &str_off);
721               attr_value.aux.shndx = shndx;
722               attr_value.val.refval = str_off;
723               break;
724             }
725           case elfcpp::DW_FORM_sec_offset:
726             {
727               off_t sec_off;
728               if (this->dwinfo_->offset_size() == 4)
729                 sec_off = this->dwinfo_->read_from_pointer<32>(&pattr);
730               else
731                 sec_off = this->dwinfo_->read_from_pointer<64>(&pattr);
732               unsigned int shndx =
733                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
734               attr_value.aux.shndx = shndx;
735               attr_value.val.refval = sec_off;
736               ref_form = true;
737               break;
738             }
739           case elfcpp::DW_FORM_addr:
740           case elfcpp::DW_FORM_ref_addr:
741             {
742               off_t sec_off;
743               if (this->dwinfo_->address_size() == 4)
744                 sec_off = this->dwinfo_->read_from_pointer<32>(&pattr);
745               else
746                 sec_off = this->dwinfo_->read_from_pointer<64>(&pattr);
747               unsigned int shndx =
748                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
749               attr_value.aux.shndx = shndx;
750               attr_value.val.refval = sec_off;
751               ref_form = true;
752               break;
753             }
754           case elfcpp::DW_FORM_block1:
755             attr_value.aux.blocklen = *pattr++;
756             attr_value.val.blockval = pattr;
757             pattr += attr_value.aux.blocklen;
758             break;
759           case elfcpp::DW_FORM_block2:
760             attr_value.aux.blocklen =
761                 this->dwinfo_->read_from_pointer<16>(&pattr);
762             attr_value.val.blockval = pattr;
763             pattr += attr_value.aux.blocklen;
764             break;
765           case elfcpp::DW_FORM_block4:
766             attr_value.aux.blocklen =
767                 this->dwinfo_->read_from_pointer<32>(&pattr);
768             attr_value.val.blockval = pattr;
769             pattr += attr_value.aux.blocklen;
770             break;
771           case elfcpp::DW_FORM_block:
772           case elfcpp::DW_FORM_exprloc:
773             attr_value.aux.blocklen = read_unsigned_LEB_128(pattr, &len);
774             attr_value.val.blockval = pattr + len;
775             pattr += len + attr_value.aux.blocklen;
776             break;
777           case elfcpp::DW_FORM_data1:
778           case elfcpp::DW_FORM_flag:
779             attr_value.val.intval = *pattr++;
780             break;
781           case elfcpp::DW_FORM_ref1:
782             attr_value.val.refval = *pattr++;
783             ref_form = true;
784             break;
785           case elfcpp::DW_FORM_data2:
786             attr_value.val.intval =
787                 this->dwinfo_->read_from_pointer<16>(&pattr);
788             break;
789           case elfcpp::DW_FORM_ref2:
790             attr_value.val.refval =
791                 this->dwinfo_->read_from_pointer<16>(&pattr);
792             ref_form = true;
793             break;
794           case elfcpp::DW_FORM_data4:
795             {
796               off_t sec_off;
797               sec_off = this->dwinfo_->read_from_pointer<32>(&pattr);
798               unsigned int shndx =
799                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
800               attr_value.aux.shndx = shndx;
801               attr_value.val.intval = sec_off;
802               break;
803             }
804           case elfcpp::DW_FORM_ref4:
805             {
806               off_t sec_off;
807               sec_off = this->dwinfo_->read_from_pointer<32>(&pattr);
808               unsigned int shndx =
809                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
810               attr_value.aux.shndx = shndx;
811               attr_value.val.refval = sec_off;
812               ref_form = true;
813               break;
814             }
815           case elfcpp::DW_FORM_data8:
816             {
817               off_t sec_off;
818               sec_off = this->dwinfo_->read_from_pointer<64>(&pattr);
819               unsigned int shndx =
820                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
821               attr_value.aux.shndx = shndx;
822               attr_value.val.intval = sec_off;
823               break;
824             }
825           case elfcpp::DW_FORM_ref_sig8:
826             attr_value.val.uintval =
827                 this->dwinfo_->read_from_pointer<64>(&pattr);
828             break;
829           case elfcpp::DW_FORM_ref8:
830             {
831               off_t sec_off;
832               sec_off = this->dwinfo_->read_from_pointer<64>(&pattr);
833               unsigned int shndx =
834                   this->dwinfo_->lookup_reloc(attr_off, &sec_off);
835               attr_value.aux.shndx = shndx;
836               attr_value.val.refval = sec_off;
837               ref_form = true;
838               break;
839             }
840           case elfcpp::DW_FORM_ref_udata:
841             attr_value.val.refval = read_unsigned_LEB_128(pattr, &len);
842             ref_form = true;
843             pattr += len;
844             break;
845           case elfcpp::DW_FORM_udata:
846           case elfcpp::DW_FORM_GNU_addr_index:
847           case elfcpp::DW_FORM_GNU_str_index:
848             attr_value.val.uintval = read_unsigned_LEB_128(pattr, &len);
849             pattr += len;
850             break;
851           case elfcpp::DW_FORM_sdata:
852             attr_value.val.intval = read_signed_LEB_128(pattr, &len);
853             pattr += len;
854             break;
855           case elfcpp::DW_FORM_string:
856             attr_value.val.stringval = reinterpret_cast<const char*>(pattr);
857             len = strlen(attr_value.val.stringval);
858             pattr += len + 1;
859             break;
860           default:
861             return false;
862         }
863
864       // Cache the most frequently-requested attributes.
865       switch (attr)
866         {
867           case elfcpp::DW_AT_name:
868             if (form == elfcpp::DW_FORM_string)
869               this->name_ = attr_value.val.stringval;
870             else if (form == elfcpp::DW_FORM_strp)
871               {
872                 // All indirect strings should refer to the same
873                 // string section, so we just save the last one seen.
874                 this->string_shndx_ = attr_value.aux.shndx;
875                 this->name_off_ = attr_value.val.refval;
876               }
877             break;
878           case elfcpp::DW_AT_linkage_name:
879           case elfcpp::DW_AT_MIPS_linkage_name:
880             if (form == elfcpp::DW_FORM_string)
881               this->linkage_name_ = attr_value.val.stringval;
882             else if (form == elfcpp::DW_FORM_strp)
883               {
884                 // All indirect strings should refer to the same
885                 // string section, so we just save the last one seen.
886                 this->string_shndx_ = attr_value.aux.shndx;
887                 this->linkage_name_off_ = attr_value.val.refval;
888               }
889             break;
890           case elfcpp::DW_AT_specification:
891             if (ref_form)
892               this->specification_ = attr_value.val.refval;
893             break;
894           case elfcpp::DW_AT_abstract_origin:
895             if (ref_form)
896               this->abstract_origin_ = attr_value.val.refval;
897             break;
898           case elfcpp::DW_AT_sibling:
899             if (ref_form && attr_value.aux.shndx == 0)
900               this->sibling_offset_ = attr_value.val.refval;
901           default:
902             break;
903         }
904
905       this->attributes_.push_back(attr_value);
906     }
907
908   // Now that we know where the next DIE begins, record the offset
909   // to avoid later recalculation.
910   if (this->has_children())
911     this->child_offset_ = this->die_offset_ + (pattr - pdie);
912   else
913     this->sibling_offset_ = this->die_offset_ + (pattr - pdie);
914
915   this->attributes_read_ = true;
916   return true;
917 }
918
919 // Skip all the attributes of the DIE and return the offset of the next DIE.
920
921 off_t
922 Dwarf_die::skip_attributes()
923 {
924   gold_assert(this->abbrev_code_ != NULL);
925
926   const unsigned char* pdie =
927       this->dwinfo_->buffer_at_offset(this->die_offset_);
928   if (pdie == NULL)
929     return 0;
930   const unsigned char* pattr = pdie + this->attr_offset_;
931
932   for (unsigned int i = 0; i < this->abbrev_code_->attributes.size(); ++i)
933     {
934       size_t len;
935       unsigned int form = this->abbrev_code_->attributes[i].form;
936       if (form == elfcpp::DW_FORM_indirect)
937         {
938           form = read_unsigned_LEB_128(pattr, &len);
939           pattr += len;
940         }
941       switch(form)
942         {
943           case elfcpp::DW_FORM_flag_present:
944             break;
945           case elfcpp::DW_FORM_strp:
946           case elfcpp::DW_FORM_sec_offset:
947             pattr += this->dwinfo_->offset_size();
948             break;
949           case elfcpp::DW_FORM_addr:
950           case elfcpp::DW_FORM_ref_addr:
951             pattr += this->dwinfo_->address_size();
952             break;
953           case elfcpp::DW_FORM_block1:
954             pattr += 1 + *pattr;
955             break;
956           case elfcpp::DW_FORM_block2:
957             {
958               uint16_t block_size;
959               block_size = this->dwinfo_->read_from_pointer<16>(&pattr);
960               pattr += block_size;
961               break;
962             }
963           case elfcpp::DW_FORM_block4:
964             {
965               uint32_t block_size;
966               block_size = this->dwinfo_->read_from_pointer<32>(&pattr);
967               pattr += block_size;
968               break;
969             }
970           case elfcpp::DW_FORM_block:
971           case elfcpp::DW_FORM_exprloc:
972             {
973               uint64_t block_size;
974               block_size = read_unsigned_LEB_128(pattr, &len);
975               pattr += len + block_size;
976               break;
977             }
978           case elfcpp::DW_FORM_data1:
979           case elfcpp::DW_FORM_ref1:
980           case elfcpp::DW_FORM_flag:
981             pattr += 1;
982             break;
983           case elfcpp::DW_FORM_data2:
984           case elfcpp::DW_FORM_ref2:
985             pattr += 2;
986             break;
987           case elfcpp::DW_FORM_data4:
988           case elfcpp::DW_FORM_ref4:
989             pattr += 4;
990             break;
991           case elfcpp::DW_FORM_data8:
992           case elfcpp::DW_FORM_ref8:
993           case elfcpp::DW_FORM_ref_sig8:
994             pattr += 8;
995             break;
996           case elfcpp::DW_FORM_ref_udata:
997           case elfcpp::DW_FORM_udata:
998           case elfcpp::DW_FORM_GNU_addr_index:
999           case elfcpp::DW_FORM_GNU_str_index:
1000             read_unsigned_LEB_128(pattr, &len);
1001             pattr += len;
1002             break;
1003           case elfcpp::DW_FORM_sdata:
1004             read_signed_LEB_128(pattr, &len);
1005             pattr += len;
1006             break;
1007           case elfcpp::DW_FORM_string:
1008             len = strlen(reinterpret_cast<const char*>(pattr));
1009             pattr += len + 1;
1010             break;
1011           default:
1012             return 0;
1013         }
1014     }
1015
1016   return this->die_offset_ + (pattr - pdie);
1017 }
1018
1019 // Get the name of the DIE and cache it.
1020
1021 void
1022 Dwarf_die::set_name()
1023 {
1024   if (this->name_ != NULL || !this->read_attributes())
1025     return;
1026   if (this->name_off_ != -1)
1027     this->name_ = this->dwinfo_->get_string(this->name_off_,
1028                                             this->string_shndx_);
1029 }
1030
1031 // Get the linkage name of the DIE and cache it.
1032
1033 void
1034 Dwarf_die::set_linkage_name()
1035 {
1036   if (this->linkage_name_ != NULL || !this->read_attributes())
1037     return;
1038   if (this->linkage_name_off_ != -1)
1039     this->linkage_name_ = this->dwinfo_->get_string(this->linkage_name_off_,
1040                                                     this->string_shndx_);
1041 }
1042
1043 // Return the value of attribute ATTR.
1044
1045 const Dwarf_die::Attribute_value*
1046 Dwarf_die::attribute(unsigned int attr)
1047 {
1048   if (!this->read_attributes())
1049     return NULL;
1050   for (unsigned int i = 0; i < this->attributes_.size(); ++i)
1051     {
1052       if (this->attributes_[i].attr == attr)
1053         return &this->attributes_[i];
1054     }
1055   return NULL;
1056 }
1057
1058 const char*
1059 Dwarf_die::string_attribute(unsigned int attr)
1060 {
1061   const Attribute_value* attr_val = this->attribute(attr);
1062   if (attr_val == NULL)
1063     return NULL;
1064   switch (attr_val->form)
1065     {
1066       case elfcpp::DW_FORM_string:
1067         return attr_val->val.stringval;
1068       case elfcpp::DW_FORM_strp:
1069         return this->dwinfo_->get_string(attr_val->val.refval,
1070                                          attr_val->aux.shndx);
1071       default:
1072         return NULL;
1073     }
1074 }
1075
1076 int64_t
1077 Dwarf_die::int_attribute(unsigned int attr)
1078 {
1079   const Attribute_value* attr_val = this->attribute(attr);
1080   if (attr_val == NULL)
1081     return 0;
1082   switch (attr_val->form)
1083     {
1084       case elfcpp::DW_FORM_flag_present:
1085       case elfcpp::DW_FORM_data1:
1086       case elfcpp::DW_FORM_flag:
1087       case elfcpp::DW_FORM_data2:
1088       case elfcpp::DW_FORM_data4:
1089       case elfcpp::DW_FORM_data8:
1090       case elfcpp::DW_FORM_sdata:
1091         return attr_val->val.intval;
1092       default:
1093         return 0;
1094     }
1095 }
1096
1097 uint64_t
1098 Dwarf_die::uint_attribute(unsigned int attr)
1099 {
1100   const Attribute_value* attr_val = this->attribute(attr);
1101   if (attr_val == NULL)
1102     return 0;
1103   switch (attr_val->form)
1104     {
1105       case elfcpp::DW_FORM_flag_present:
1106       case elfcpp::DW_FORM_data1:
1107       case elfcpp::DW_FORM_flag:
1108       case elfcpp::DW_FORM_data4:
1109       case elfcpp::DW_FORM_data8:
1110       case elfcpp::DW_FORM_ref_sig8:
1111       case elfcpp::DW_FORM_udata:
1112         return attr_val->val.uintval;
1113       default:
1114         return 0;
1115     }
1116 }
1117
1118 off_t
1119 Dwarf_die::ref_attribute(unsigned int attr, unsigned int* shndx)
1120 {
1121   const Attribute_value* attr_val = this->attribute(attr);
1122   if (attr_val == NULL)
1123     return -1;
1124   switch (attr_val->form)
1125     {
1126       case elfcpp::DW_FORM_sec_offset:
1127       case elfcpp::DW_FORM_addr:
1128       case elfcpp::DW_FORM_ref_addr:
1129       case elfcpp::DW_FORM_ref1:
1130       case elfcpp::DW_FORM_ref2:
1131       case elfcpp::DW_FORM_ref4:
1132       case elfcpp::DW_FORM_ref8:
1133       case elfcpp::DW_FORM_ref_udata:
1134         *shndx = attr_val->aux.shndx;
1135         return attr_val->val.refval;
1136       case elfcpp::DW_FORM_ref_sig8:
1137         *shndx = attr_val->aux.shndx;
1138         return attr_val->val.uintval;
1139       case elfcpp::DW_FORM_data4:
1140       case elfcpp::DW_FORM_data8:
1141         *shndx = attr_val->aux.shndx;
1142         return attr_val->val.intval;
1143       default:
1144         return -1;
1145     }
1146 }
1147
1148 off_t
1149 Dwarf_die::address_attribute(unsigned int attr, unsigned int* shndx)
1150 {
1151   const Attribute_value* attr_val = this->attribute(attr);
1152   if (attr_val == NULL || attr_val->form != elfcpp::DW_FORM_addr)
1153     return -1;
1154
1155   *shndx = attr_val->aux.shndx;
1156   return attr_val->val.refval;
1157 }
1158
1159 // Return the offset of this DIE's first child.
1160
1161 off_t
1162 Dwarf_die::child_offset()
1163 {
1164   gold_assert(this->abbrev_code_ != NULL);
1165   if (!this->has_children())
1166     return 0;
1167   if (this->child_offset_ == 0)
1168     this->child_offset_ = this->skip_attributes();
1169   return this->child_offset_;
1170 }
1171
1172 // Return the offset of this DIE's next sibling.
1173
1174 off_t
1175 Dwarf_die::sibling_offset()
1176 {
1177   gold_assert(this->abbrev_code_ != NULL);
1178
1179   if (this->sibling_offset_ != 0)
1180     return this->sibling_offset_;
1181
1182   if (!this->has_children())
1183     {
1184       this->sibling_offset_ = this->skip_attributes();
1185       return this->sibling_offset_;
1186     }
1187
1188   if (this->has_sibling_attribute())
1189     {
1190       if (!this->read_attributes())
1191         return 0;
1192       if (this->sibling_offset_ != 0)
1193         return this->sibling_offset_;
1194     }
1195
1196   // Skip over the children.
1197   off_t child_offset = this->child_offset();
1198   while (child_offset > 0)
1199     {
1200       Dwarf_die die(this->dwinfo_, child_offset, this);
1201       // The Dwarf_die ctor will set this DIE's sibling offset
1202       // when it reads a zero abbrev code.
1203       if (die.tag() == 0)
1204         break;
1205       child_offset = die.sibling_offset();
1206     }
1207
1208   // This should be set by now.  If not, there was a problem reading
1209   // the DWARF info, and we return 0.
1210   return this->sibling_offset_;
1211 }
1212
1213 // class Dwarf_info_reader
1214
1215 // Begin parsing the debug info.  This calls visit_compilation_unit()
1216 // or visit_type_unit() for each compilation or type unit found in the
1217 // section, and visit_die() for each top-level DIE.
1218
1219 void
1220 Dwarf_info_reader::parse()
1221 {
1222   if (this->object_->is_big_endian())
1223     {
1224 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1225       this->do_parse<true>();
1226 #else
1227       gold_unreachable();
1228 #endif
1229     }
1230   else
1231     {
1232 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1233       this->do_parse<false>();
1234 #else
1235       gold_unreachable();
1236 #endif
1237     }
1238 }
1239
1240 template<bool big_endian>
1241 void
1242 Dwarf_info_reader::do_parse()
1243 {
1244   // Get the section contents and decompress if necessary.
1245   section_size_type buffer_size;
1246   bool buffer_is_new;
1247   this->buffer_ = this->object_->decompressed_section_contents(this->shndx_,
1248                                                                &buffer_size,
1249                                                                &buffer_is_new);
1250   if (this->buffer_ == NULL || buffer_size == 0)
1251     return;
1252   this->buffer_end_ = this->buffer_ + buffer_size;
1253
1254   // The offset of this input section in the output section.
1255   off_t section_offset = this->object_->output_section_offset(this->shndx_);
1256
1257   // Start tracking relocations for this section.
1258   this->reloc_mapper_ = make_elf_reloc_mapper(this->object_, this->symtab_,
1259                                               this->symtab_size_);
1260   this->reloc_mapper_->initialize(this->reloc_shndx_, this->reloc_type_);
1261
1262   // Loop over compilation units (or type units).
1263   unsigned int abbrev_shndx = this->abbrev_shndx_;
1264   off_t abbrev_offset = 0;
1265   const unsigned char* pinfo = this->buffer_;
1266   while (pinfo < this->buffer_end_)
1267     {
1268       // Read the compilation (or type) unit header.
1269       const unsigned char* cu_start = pinfo;
1270       this->cu_offset_ = cu_start - this->buffer_;
1271       this->cu_length_ = this->buffer_end_ - cu_start;
1272
1273       // Read unit_length (4 or 12 bytes).
1274       if (!this->check_buffer(pinfo + 4))
1275         break;
1276       uint32_t unit_length =
1277           elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo);
1278       pinfo += 4;
1279       if (unit_length == 0xffffffff)
1280         {
1281           if (!this->check_buffer(pinfo + 8))
1282             break;
1283           unit_length = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo);
1284           pinfo += 8;
1285           this->offset_size_ = 8;
1286         }
1287       else
1288         this->offset_size_ = 4;
1289       if (!this->check_buffer(pinfo + unit_length))
1290         break;
1291       const unsigned char* cu_end = pinfo + unit_length;
1292       this->cu_length_ = cu_end - cu_start;
1293       if (!this->check_buffer(pinfo + 2 + this->offset_size_ + 1))
1294         break;
1295
1296       // Read version (2 bytes).
1297       this->cu_version_ =
1298           elfcpp::Swap_unaligned<16, big_endian>::readval(pinfo);
1299       pinfo += 2;
1300
1301       // Read debug_abbrev_offset (4 or 8 bytes).
1302       if (this->offset_size_ == 4)
1303         abbrev_offset = elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo);
1304       else
1305         abbrev_offset = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo);
1306       if (this->reloc_shndx_ > 0)
1307         {
1308           off_t reloc_offset = pinfo - this->buffer_;
1309           off_t value;
1310           abbrev_shndx =
1311               this->reloc_mapper_->get_reloc_target(reloc_offset, &value);
1312           if (abbrev_shndx == 0)
1313             return;
1314           if (this->reloc_type_ == elfcpp::SHT_REL)
1315             abbrev_offset += value;
1316           else
1317             abbrev_offset = value;
1318         }
1319       pinfo += this->offset_size_;
1320
1321       // Read address_size (1 byte).
1322       this->address_size_ = *pinfo++;
1323
1324       // For type units, read the two extra fields.
1325       uint64_t signature = 0;
1326       off_t type_offset = 0;
1327       if (this->is_type_unit_)
1328         {
1329           if (!this->check_buffer(pinfo + 8 + this->offset_size_))
1330             break;
1331
1332           // Read type_signature (8 bytes).
1333           signature = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo);
1334           pinfo += 8;
1335
1336           // Read type_offset (4 or 8 bytes).
1337           if (this->offset_size_ == 4)
1338             type_offset =
1339                 elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo);
1340           else
1341             type_offset =
1342                 elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo);
1343           pinfo += this->offset_size_;
1344         }
1345
1346       // Read the .debug_abbrev table.
1347       this->abbrev_table_.read_abbrevs(this->object_, abbrev_shndx,
1348                                        abbrev_offset);
1349
1350       // Visit the root DIE.
1351       Dwarf_die root_die(this,
1352                          pinfo - (this->buffer_ + this->cu_offset_),
1353                          NULL);
1354       if (root_die.tag() != 0)
1355         {
1356           // Visit the CU or TU.
1357           if (this->is_type_unit_)
1358             this->visit_type_unit(section_offset + this->cu_offset_,
1359                                   cu_end - cu_start, type_offset, signature,
1360                                   &root_die);
1361           else
1362             this->visit_compilation_unit(section_offset + this->cu_offset_,
1363                                          cu_end - cu_start, &root_die);
1364         }
1365
1366       // Advance to the next CU.
1367       pinfo = cu_end;
1368     }
1369
1370   if (buffer_is_new)
1371     {
1372       delete[] this->buffer_;
1373       this->buffer_ = NULL;
1374     }
1375 }
1376
1377 // Read the DWARF string table.
1378
1379 bool
1380 Dwarf_info_reader::do_read_string_table(unsigned int string_shndx)
1381 {
1382   Relobj* object = this->object_;
1383
1384   // If we don't have relocations, string_shndx will be 0, and
1385   // we'll have to hunt for the .debug_str section.
1386   if (string_shndx == 0)
1387     {
1388       for (unsigned int i = 1; i < this->object_->shnum(); ++i)
1389         {
1390           std::string name = object->section_name(i);
1391           if (name == ".debug_str" || name == ".zdebug_str")
1392             {
1393               string_shndx = i;
1394               this->string_output_section_offset_ =
1395                   object->output_section_offset(i);
1396               break;
1397             }
1398         }
1399       if (string_shndx == 0)
1400         return false;
1401     }
1402
1403   if (this->owns_string_buffer_ && this->string_buffer_ != NULL)
1404     {
1405       delete[] this->string_buffer_;
1406       this->owns_string_buffer_ = false;
1407     }
1408
1409   // Get the secton contents and decompress if necessary.
1410   section_size_type buffer_size;
1411   const unsigned char* buffer =
1412       object->decompressed_section_contents(string_shndx,
1413                                             &buffer_size,
1414                                             &this->owns_string_buffer_);
1415   this->string_buffer_ = reinterpret_cast<const char*>(buffer);
1416   this->string_buffer_end_ = this->string_buffer_ + buffer_size;
1417   this->string_shndx_ = string_shndx;
1418   return true;
1419 }
1420
1421 // Read a possibly unaligned integer of SIZE.
1422 template <int valsize>
1423 inline typename elfcpp::Valtype_base<valsize>::Valtype
1424 Dwarf_info_reader::read_from_pointer(const unsigned char* source)
1425 {
1426   typename elfcpp::Valtype_base<valsize>::Valtype return_value;
1427   if (this->object_->is_big_endian())
1428     return_value = elfcpp::Swap_unaligned<valsize, true>::readval(source);
1429   else
1430     return_value = elfcpp::Swap_unaligned<valsize, false>::readval(source);
1431   return return_value;
1432 }
1433
1434 // Read a possibly unaligned integer of SIZE.  Update SOURCE after read.
1435 template <int valsize>
1436 inline typename elfcpp::Valtype_base<valsize>::Valtype
1437 Dwarf_info_reader::read_from_pointer(const unsigned char** source)
1438 {
1439   typename elfcpp::Valtype_base<valsize>::Valtype return_value;
1440   if (this->object_->is_big_endian())
1441     return_value = elfcpp::Swap_unaligned<valsize, true>::readval(*source);
1442   else
1443     return_value = elfcpp::Swap_unaligned<valsize, false>::readval(*source);
1444   *source += valsize / 8;
1445   return return_value;
1446 }
1447
1448 // Look for a relocation at offset ATTR_OFF in the dwarf info,
1449 // and return the section index and offset of the target.
1450
1451 unsigned int
1452 Dwarf_info_reader::lookup_reloc(off_t attr_off, off_t* target_off)
1453 {
1454   off_t value;
1455   attr_off += this->cu_offset_;
1456   unsigned int shndx = this->reloc_mapper_->get_reloc_target(attr_off, &value);
1457   if (shndx == 0)
1458     return 0;
1459   if (this->reloc_type_ == elfcpp::SHT_REL)
1460     *target_off += value;
1461   else
1462     *target_off = value;
1463   return shndx;
1464 }
1465
1466 // Return a string from the DWARF string table.
1467
1468 const char*
1469 Dwarf_info_reader::get_string(off_t str_off, unsigned int string_shndx)
1470 {
1471   if (!this->read_string_table(string_shndx))
1472     return NULL;
1473
1474   // Correct the offset.  For incremental update links, we have a
1475   // relocated offset that is relative to the output section, but
1476   // here we need an offset relative to the input section.
1477   str_off -= this->string_output_section_offset_;
1478
1479   const char* p = this->string_buffer_ + str_off;
1480
1481   if (p < this->string_buffer_ || p >= this->string_buffer_end_)
1482     return NULL;
1483
1484   return p;
1485 }
1486
1487 // The following are default, do-nothing, implementations of the
1488 // hook methods normally provided by a derived class.  We provide
1489 // default implementations rather than no implementation so that
1490 // a derived class needs to implement only the hooks that it needs
1491 // to use.
1492
1493 // Process a compilation unit and parse its child DIE.
1494
1495 void
1496 Dwarf_info_reader::visit_compilation_unit(off_t, off_t, Dwarf_die*)
1497 {
1498 }
1499
1500 // Process a type unit and parse its child DIE.
1501
1502 void
1503 Dwarf_info_reader::visit_type_unit(off_t, off_t, off_t, uint64_t, Dwarf_die*)
1504 {
1505 }
1506
1507 // Print a warning about a corrupt debug section.
1508
1509 void
1510 Dwarf_info_reader::warn_corrupt_debug_section() const
1511 {
1512   gold_warning(_("%s: corrupt debug info in %s"),
1513                this->object_->name().c_str(),
1514                this->object_->section_name(this->shndx_).c_str());
1515 }
1516
1517 // class Sized_dwarf_line_info
1518
1519 struct LineStateMachine
1520 {
1521   int file_num;
1522   uint64_t address;
1523   int line_num;
1524   int column_num;
1525   unsigned int shndx;    // the section address refers to
1526   bool is_stmt;          // stmt means statement.
1527   bool basic_block;
1528   bool end_sequence;
1529 };
1530
1531 static void
1532 ResetLineStateMachine(struct LineStateMachine* lsm, bool default_is_stmt)
1533 {
1534   lsm->file_num = 1;
1535   lsm->address = 0;
1536   lsm->line_num = 1;
1537   lsm->column_num = 0;
1538   lsm->shndx = -1U;
1539   lsm->is_stmt = default_is_stmt;
1540   lsm->basic_block = false;
1541   lsm->end_sequence = false;
1542 }
1543
1544 template<int size, bool big_endian>
1545 Sized_dwarf_line_info<size, big_endian>::Sized_dwarf_line_info(
1546     Object* object,
1547     unsigned int read_shndx)
1548   : data_valid_(false), buffer_(NULL), buffer_start_(NULL),
1549     reloc_mapper_(NULL), symtab_buffer_(NULL), directories_(), files_(),
1550     current_header_index_(-1)
1551 {
1552   unsigned int debug_shndx;
1553
1554   for (debug_shndx = 1; debug_shndx < object->shnum(); ++debug_shndx)
1555     {
1556       // FIXME: do this more efficiently: section_name() isn't super-fast
1557       std::string name = object->section_name(debug_shndx);
1558       if (name == ".debug_line" || name == ".zdebug_line")
1559         {
1560           section_size_type buffer_size;
1561           bool is_new = false;
1562           this->buffer_ = object->decompressed_section_contents(debug_shndx,
1563                                                                 &buffer_size,
1564                                                                 &is_new);
1565           if (is_new)
1566             this->buffer_start_ = this->buffer_;
1567           this->buffer_end_ = this->buffer_ + buffer_size;
1568           break;
1569         }
1570     }
1571   if (this->buffer_ == NULL)
1572     return;
1573
1574   // Find the relocation section for ".debug_line".
1575   // We expect these for relobjs (.o's) but not dynobjs (.so's).
1576   unsigned int reloc_shndx = 0;
1577   for (unsigned int i = 0; i < object->shnum(); ++i)
1578     {
1579       unsigned int reloc_sh_type = object->section_type(i);
1580       if ((reloc_sh_type == elfcpp::SHT_REL
1581            || reloc_sh_type == elfcpp::SHT_RELA)
1582           && object->section_info(i) == debug_shndx)
1583         {
1584           reloc_shndx = i;
1585           this->track_relocs_type_ = reloc_sh_type;
1586           break;
1587         }
1588     }
1589
1590   // Finally, we need the symtab section to interpret the relocs.
1591   if (reloc_shndx != 0)
1592     {
1593       unsigned int symtab_shndx;
1594       for (symtab_shndx = 0; symtab_shndx < object->shnum(); ++symtab_shndx)
1595         if (object->section_type(symtab_shndx) == elfcpp::SHT_SYMTAB)
1596           {
1597             this->symtab_buffer_ = object->section_contents(
1598                 symtab_shndx, &this->symtab_buffer_size_, false);
1599             break;
1600           }
1601       if (this->symtab_buffer_ == NULL)
1602         return;
1603     }
1604
1605   this->reloc_mapper_ =
1606       new Sized_elf_reloc_mapper<size, big_endian>(object,
1607                                                    this->symtab_buffer_,
1608                                                    this->symtab_buffer_size_);
1609   if (!this->reloc_mapper_->initialize(reloc_shndx, this->track_relocs_type_))
1610     return;
1611
1612   // Now that we have successfully read all the data, parse the debug
1613   // info.
1614   this->data_valid_ = true;
1615   this->read_line_mappings(read_shndx);
1616 }
1617
1618 // Read the DWARF header.
1619
1620 template<int size, bool big_endian>
1621 const unsigned char*
1622 Sized_dwarf_line_info<size, big_endian>::read_header_prolog(
1623     const unsigned char* lineptr)
1624 {
1625   uint32_t initial_length = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr);
1626   lineptr += 4;
1627
1628   // In DWARF2/3, if the initial length is all 1 bits, then the offset
1629   // size is 8 and we need to read the next 8 bytes for the real length.
1630   if (initial_length == 0xffffffff)
1631     {
1632       header_.offset_size = 8;
1633       initial_length = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr);
1634       lineptr += 8;
1635     }
1636   else
1637     header_.offset_size = 4;
1638
1639   header_.total_length = initial_length;
1640
1641   gold_assert(lineptr + header_.total_length <= buffer_end_);
1642
1643   header_.version = elfcpp::Swap_unaligned<16, big_endian>::readval(lineptr);
1644   lineptr += 2;
1645
1646   if (header_.offset_size == 4)
1647     header_.prologue_length = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr);
1648   else
1649     header_.prologue_length = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr);
1650   lineptr += header_.offset_size;
1651
1652   header_.min_insn_length = *lineptr;
1653   lineptr += 1;
1654
1655   header_.default_is_stmt = *lineptr;
1656   lineptr += 1;
1657
1658   header_.line_base = *reinterpret_cast<const signed char*>(lineptr);
1659   lineptr += 1;
1660
1661   header_.line_range = *lineptr;
1662   lineptr += 1;
1663
1664   header_.opcode_base = *lineptr;
1665   lineptr += 1;
1666
1667   header_.std_opcode_lengths.resize(header_.opcode_base + 1);
1668   header_.std_opcode_lengths[0] = 0;
1669   for (int i = 1; i < header_.opcode_base; i++)
1670     {
1671       header_.std_opcode_lengths[i] = *lineptr;
1672       lineptr += 1;
1673     }
1674
1675   return lineptr;
1676 }
1677
1678 // The header for a debug_line section is mildly complicated, because
1679 // the line info is very tightly encoded.
1680
1681 template<int size, bool big_endian>
1682 const unsigned char*
1683 Sized_dwarf_line_info<size, big_endian>::read_header_tables(
1684     const unsigned char* lineptr)
1685 {
1686   ++this->current_header_index_;
1687
1688   // Create a new directories_ entry and a new files_ entry for our new
1689   // header.  We initialize each with a single empty element, because
1690   // dwarf indexes directory and filenames starting at 1.
1691   gold_assert(static_cast<int>(this->directories_.size())
1692               == this->current_header_index_);
1693   gold_assert(static_cast<int>(this->files_.size())
1694               == this->current_header_index_);
1695   this->directories_.push_back(std::vector<std::string>(1));
1696   this->files_.push_back(std::vector<std::pair<int, std::string> >(1));
1697
1698   // It is legal for the directory entry table to be empty.
1699   if (*lineptr)
1700     {
1701       int dirindex = 1;
1702       while (*lineptr)
1703         {
1704           const char* dirname = reinterpret_cast<const char*>(lineptr);
1705           gold_assert(dirindex
1706                       == static_cast<int>(this->directories_.back().size()));
1707           this->directories_.back().push_back(dirname);
1708           lineptr += this->directories_.back().back().size() + 1;
1709           dirindex++;
1710         }
1711     }
1712   lineptr++;
1713
1714   // It is also legal for the file entry table to be empty.
1715   if (*lineptr)
1716     {
1717       int fileindex = 1;
1718       size_t len;
1719       while (*lineptr)
1720         {
1721           const char* filename = reinterpret_cast<const char*>(lineptr);
1722           lineptr += strlen(filename) + 1;
1723
1724           uint64_t dirindex = read_unsigned_LEB_128(lineptr, &len);
1725           lineptr += len;
1726
1727           if (dirindex >= this->directories_.back().size())
1728             dirindex = 0;
1729           int dirindexi = static_cast<int>(dirindex);
1730
1731           read_unsigned_LEB_128(lineptr, &len);   // mod_time
1732           lineptr += len;
1733
1734           read_unsigned_LEB_128(lineptr, &len);   // filelength
1735           lineptr += len;
1736
1737           gold_assert(fileindex
1738                       == static_cast<int>(this->files_.back().size()));
1739           this->files_.back().push_back(std::make_pair(dirindexi, filename));
1740           fileindex++;
1741         }
1742     }
1743   lineptr++;
1744
1745   return lineptr;
1746 }
1747
1748 // Process a single opcode in the .debug.line structure.
1749
1750 template<int size, bool big_endian>
1751 bool
1752 Sized_dwarf_line_info<size, big_endian>::process_one_opcode(
1753     const unsigned char* start, struct LineStateMachine* lsm, size_t* len)
1754 {
1755   size_t oplen = 0;
1756   size_t templen;
1757   unsigned char opcode = *start;
1758   oplen++;
1759   start++;
1760
1761   // If the opcode is great than the opcode_base, it is a special
1762   // opcode. Most line programs consist mainly of special opcodes.
1763   if (opcode >= header_.opcode_base)
1764     {
1765       opcode -= header_.opcode_base;
1766       const int advance_address = ((opcode / header_.line_range)
1767                                    * header_.min_insn_length);
1768       lsm->address += advance_address;
1769
1770       const int advance_line = ((opcode % header_.line_range)
1771                                 + header_.line_base);
1772       lsm->line_num += advance_line;
1773       lsm->basic_block = true;
1774       *len = oplen;
1775       return true;
1776     }
1777
1778   // Otherwise, we have the regular opcodes
1779   switch (opcode)
1780     {
1781     case elfcpp::DW_LNS_copy:
1782       lsm->basic_block = false;
1783       *len = oplen;
1784       return true;
1785
1786     case elfcpp::DW_LNS_advance_pc:
1787       {
1788         const uint64_t advance_address
1789             = read_unsigned_LEB_128(start, &templen);
1790         oplen += templen;
1791         lsm->address += header_.min_insn_length * advance_address;
1792       }
1793       break;
1794
1795     case elfcpp::DW_LNS_advance_line:
1796       {
1797         const uint64_t advance_line = read_signed_LEB_128(start, &templen);
1798         oplen += templen;
1799         lsm->line_num += advance_line;
1800       }
1801       break;
1802
1803     case elfcpp::DW_LNS_set_file:
1804       {
1805         const uint64_t fileno = read_unsigned_LEB_128(start, &templen);
1806         oplen += templen;
1807         lsm->file_num = fileno;
1808       }
1809       break;
1810
1811     case elfcpp::DW_LNS_set_column:
1812       {
1813         const uint64_t colno = read_unsigned_LEB_128(start, &templen);
1814         oplen += templen;
1815         lsm->column_num = colno;
1816       }
1817       break;
1818
1819     case elfcpp::DW_LNS_negate_stmt:
1820       lsm->is_stmt = !lsm->is_stmt;
1821       break;
1822
1823     case elfcpp::DW_LNS_set_basic_block:
1824       lsm->basic_block = true;
1825       break;
1826
1827     case elfcpp::DW_LNS_fixed_advance_pc:
1828       {
1829         int advance_address;
1830         advance_address = elfcpp::Swap_unaligned<16, big_endian>::readval(start);
1831         oplen += 2;
1832         lsm->address += advance_address;
1833       }
1834       break;
1835
1836     case elfcpp::DW_LNS_const_add_pc:
1837       {
1838         const int advance_address = (header_.min_insn_length
1839                                      * ((255 - header_.opcode_base)
1840                                         / header_.line_range));
1841         lsm->address += advance_address;
1842       }
1843       break;
1844
1845     case elfcpp::DW_LNS_extended_op:
1846       {
1847         const uint64_t extended_op_len
1848             = read_unsigned_LEB_128(start, &templen);
1849         start += templen;
1850         oplen += templen + extended_op_len;
1851
1852         const unsigned char extended_op = *start;
1853         start++;
1854
1855         switch (extended_op)
1856           {
1857           case elfcpp::DW_LNE_end_sequence:
1858             // This means that the current byte is the one immediately
1859             // after a set of instructions.  Record the current line
1860             // for up to one less than the current address.
1861             lsm->line_num = -1;
1862             lsm->end_sequence = true;
1863             *len = oplen;
1864             return true;
1865
1866           case elfcpp::DW_LNE_set_address:
1867             {
1868               lsm->address =
1869                 elfcpp::Swap_unaligned<size, big_endian>::readval(start);
1870               typename Reloc_map::const_iterator it
1871                   = this->reloc_map_.find(start - this->buffer_);
1872               if (it != reloc_map_.end())
1873                 {
1874                   // If this is a SHT_RELA section, then ignore the
1875                   // section contents.  This assumes that this is a
1876                   // straight reloc which just uses the reloc addend.
1877                   // The reloc addend has already been included in the
1878                   // symbol value.
1879                   if (this->track_relocs_type_ == elfcpp::SHT_RELA)
1880                     lsm->address = 0;
1881                   // Add in the symbol value.
1882                   lsm->address += it->second.second;
1883                   lsm->shndx = it->second.first;
1884                 }
1885               else
1886                 {
1887                   // If we're a normal .o file, with relocs, every
1888                   // set_address should have an associated relocation.
1889                   if (this->input_is_relobj())
1890                     this->data_valid_ = false;
1891                 }
1892               break;
1893             }
1894           case elfcpp::DW_LNE_define_file:
1895             {
1896               const char* filename  = reinterpret_cast<const char*>(start);
1897               templen = strlen(filename) + 1;
1898               start += templen;
1899
1900               uint64_t dirindex = read_unsigned_LEB_128(start, &templen);
1901
1902               if (dirindex >= this->directories_.back().size())
1903                 dirindex = 0;
1904               int dirindexi = static_cast<int>(dirindex);
1905
1906               // This opcode takes two additional ULEB128 parameters
1907               // (mod_time and filelength), but we don't use those
1908               // values.  Because OPLEN already tells us how far to
1909               // skip to the next opcode, we don't need to read
1910               // them at all.
1911
1912               this->files_.back().push_back(std::make_pair(dirindexi,
1913                                                            filename));
1914             }
1915             break;
1916           }
1917       }
1918       break;
1919
1920     default:
1921       {
1922         // Ignore unknown opcode  silently
1923         for (int i = 0; i < header_.std_opcode_lengths[opcode]; i++)
1924           {
1925             size_t templen;
1926             read_unsigned_LEB_128(start, &templen);
1927             start += templen;
1928             oplen += templen;
1929           }
1930       }
1931       break;
1932   }
1933   *len = oplen;
1934   return false;
1935 }
1936
1937 // Read the debug information at LINEPTR and store it in the line
1938 // number map.
1939
1940 template<int size, bool big_endian>
1941 unsigned const char*
1942 Sized_dwarf_line_info<size, big_endian>::read_lines(unsigned const char* lineptr,
1943                                                     unsigned int shndx)
1944 {
1945   struct LineStateMachine lsm;
1946
1947   // LENGTHSTART is the place the length field is based on.  It is the
1948   // point in the header after the initial length field.
1949   const unsigned char* lengthstart = buffer_;
1950
1951   // In 64 bit dwarf, the initial length is 12 bytes, because of the
1952   // 0xffffffff at the start.
1953   if (header_.offset_size == 8)
1954     lengthstart += 12;
1955   else
1956     lengthstart += 4;
1957
1958   while (lineptr < lengthstart + header_.total_length)
1959     {
1960       ResetLineStateMachine(&lsm, header_.default_is_stmt);
1961       while (!lsm.end_sequence)
1962         {
1963           size_t oplength;
1964           bool add_line = this->process_one_opcode(lineptr, &lsm, &oplength);
1965           if (add_line
1966               && (shndx == -1U || lsm.shndx == -1U || shndx == lsm.shndx))
1967             {
1968               Offset_to_lineno_entry entry
1969                   = { static_cast<off_t>(lsm.address),
1970                       this->current_header_index_,
1971                       static_cast<unsigned int>(lsm.file_num),
1972                       true, lsm.line_num };
1973               std::vector<Offset_to_lineno_entry>&
1974                 map(this->line_number_map_[lsm.shndx]);
1975               // If we see two consecutive entries with the same
1976               // offset and a real line number, then mark the first
1977               // one as non-canonical.
1978               if (!map.empty()
1979                   && (map.back().offset == static_cast<off_t>(lsm.address))
1980                   && lsm.line_num != -1
1981                   && map.back().line_num != -1)
1982                 map.back().last_line_for_offset = false;
1983               map.push_back(entry);
1984             }
1985           lineptr += oplength;
1986         }
1987     }
1988
1989   return lengthstart + header_.total_length;
1990 }
1991
1992 // Read the relocations into a Reloc_map.
1993
1994 template<int size, bool big_endian>
1995 void
1996 Sized_dwarf_line_info<size, big_endian>::read_relocs()
1997 {
1998   if (this->symtab_buffer_ == NULL)
1999     return;
2000
2001   off_t value;
2002   off_t reloc_offset;
2003   while ((reloc_offset = this->reloc_mapper_->next_offset()) != -1)
2004     {
2005       const unsigned int shndx =
2006           this->reloc_mapper_->get_reloc_target(reloc_offset, &value);
2007
2008       // There is no reason to record non-ordinary section indexes, or
2009       // SHN_UNDEF, because they will never match the real section.
2010       if (shndx != 0)
2011         this->reloc_map_[reloc_offset] = std::make_pair(shndx, value);
2012
2013       this->reloc_mapper_->advance(reloc_offset + 1);
2014     }
2015 }
2016
2017 // Read the line number info.
2018
2019 template<int size, bool big_endian>
2020 void
2021 Sized_dwarf_line_info<size, big_endian>::read_line_mappings(unsigned int shndx)
2022 {
2023   gold_assert(this->data_valid_ == true);
2024
2025   this->read_relocs();
2026   while (this->buffer_ < this->buffer_end_)
2027     {
2028       const unsigned char* lineptr = this->buffer_;
2029       lineptr = this->read_header_prolog(lineptr);
2030       lineptr = this->read_header_tables(lineptr);
2031       lineptr = this->read_lines(lineptr, shndx);
2032       this->buffer_ = lineptr;
2033     }
2034
2035   // Sort the lines numbers, so addr2line can use binary search.
2036   for (typename Lineno_map::iterator it = line_number_map_.begin();
2037        it != line_number_map_.end();
2038        ++it)
2039     // Each vector needs to be sorted by offset.
2040     std::sort(it->second.begin(), it->second.end());
2041 }
2042
2043 // Some processing depends on whether the input is a .o file or not.
2044 // For instance, .o files have relocs, and have .debug_lines
2045 // information on a per section basis.  .so files, on the other hand,
2046 // lack relocs, and offsets are unique, so we can ignore the section
2047 // information.
2048
2049 template<int size, bool big_endian>
2050 bool
2051 Sized_dwarf_line_info<size, big_endian>::input_is_relobj()
2052 {
2053   // Only .o files have relocs and the symtab buffer that goes with them.
2054   return this->symtab_buffer_ != NULL;
2055 }
2056
2057 // Given an Offset_to_lineno_entry vector, and an offset, figure out
2058 // if the offset points into a function according to the vector (see
2059 // comments below for the algorithm).  If it does, return an iterator
2060 // into the vector that points to the line-number that contains that
2061 // offset.  If not, it returns vector::end().
2062
2063 static std::vector<Offset_to_lineno_entry>::const_iterator
2064 offset_to_iterator(const std::vector<Offset_to_lineno_entry>* offsets,
2065                    off_t offset)
2066 {
2067   const Offset_to_lineno_entry lookup_key = { offset, 0, 0, true, 0 };
2068
2069   // lower_bound() returns the smallest offset which is >= lookup_key.
2070   // If no offset in offsets is >= lookup_key, returns end().
2071   std::vector<Offset_to_lineno_entry>::const_iterator it
2072       = std::lower_bound(offsets->begin(), offsets->end(), lookup_key);
2073
2074   // This code is easiest to understand with a concrete example.
2075   // Here's a possible offsets array:
2076   // {{offset = 3211, header_num = 0, file_num = 1, last, line_num = 16},  // 0
2077   //  {offset = 3224, header_num = 0, file_num = 1, last, line_num = 20},  // 1
2078   //  {offset = 3226, header_num = 0, file_num = 1, last, line_num = 22},  // 2
2079   //  {offset = 3231, header_num = 0, file_num = 1, last, line_num = 25},  // 3
2080   //  {offset = 3232, header_num = 0, file_num = 1, last, line_num = -1},  // 4
2081   //  {offset = 3232, header_num = 0, file_num = 1, last, line_num = 65},  // 5
2082   //  {offset = 3235, header_num = 0, file_num = 1, last, line_num = 66},  // 6
2083   //  {offset = 3236, header_num = 0, file_num = 1, last, line_num = -1},  // 7
2084   //  {offset = 5764, header_num = 0, file_num = 1, last, line_num = 48},  // 8
2085   //  {offset = 5764, header_num = 0, file_num = 1,!last, line_num = 47},  // 9
2086   //  {offset = 5765, header_num = 0, file_num = 1, last, line_num = 49},  // 10
2087   //  {offset = 5767, header_num = 0, file_num = 1, last, line_num = 50},  // 11
2088   //  {offset = 5768, header_num = 0, file_num = 1, last, line_num = 51},  // 12
2089   //  {offset = 5773, header_num = 0, file_num = 1, last, line_num = -1},  // 13
2090   //  {offset = 5787, header_num = 1, file_num = 1, last, line_num = 19},  // 14
2091   //  {offset = 5790, header_num = 1, file_num = 1, last, line_num = 20},  // 15
2092   //  {offset = 5793, header_num = 1, file_num = 1, last, line_num = 67},  // 16
2093   //  {offset = 5793, header_num = 1, file_num = 1, last, line_num = -1},  // 17
2094   //  {offset = 5793, header_num = 1, file_num = 1,!last, line_num = 66},  // 18
2095   //  {offset = 5795, header_num = 1, file_num = 1, last, line_num = 68},  // 19
2096   //  {offset = 5798, header_num = 1, file_num = 1, last, line_num = -1},  // 20
2097   // The entries with line_num == -1 mark the end of a function: the
2098   // associated offset is one past the last instruction in the
2099   // function.  This can correspond to the beginning of the next
2100   // function (as is true for offset 3232); alternately, there can be
2101   // a gap between the end of one function and the start of the next
2102   // (as is true for some others, most obviously from 3236->5764).
2103   //
2104   // Case 1: lookup_key has offset == 10.  lower_bound returns
2105   //         offsets[0].  Since it's not an exact match and we're
2106   //         at the beginning of offsets, we return end() (invalid).
2107   // Case 2: lookup_key has offset 10000.  lower_bound returns
2108   //         offset[21] (end()).  We return end() (invalid).
2109   // Case 3: lookup_key has offset == 3211.  lower_bound matches
2110   //         offsets[0] exactly, and that's the entry we return.
2111   // Case 4: lookup_key has offset == 3232.  lower_bound returns
2112   //         offsets[4].  That's an exact match, but indicates
2113   //         end-of-function.  We check if offsets[5] is also an
2114   //         exact match but not end-of-function.  It is, so we
2115   //         return offsets[5].
2116   // Case 5: lookup_key has offset == 3214.  lower_bound returns
2117   //         offsets[1].  Since it's not an exact match, we back
2118   //         up to the offset that's < lookup_key, offsets[0].
2119   //         We note offsets[0] is a valid entry (not end-of-function),
2120   //         so that's the entry we return.
2121   // Case 6: lookup_key has offset == 4000.  lower_bound returns
2122   //         offsets[8].  Since it's not an exact match, we back
2123   //         up to offsets[7].  Since offsets[7] indicates
2124   //         end-of-function, we know lookup_key is between
2125   //         functions, so we return end() (not a valid offset).
2126   // Case 7: lookup_key has offset == 5794.  lower_bound returns
2127   //         offsets[19].  Since it's not an exact match, we back
2128   //         up to offsets[16].  Note we back up to the *first*
2129   //         entry with offset 5793, not just offsets[19-1].
2130   //         We note offsets[16] is a valid entry, so we return it.
2131   //         If offsets[16] had had line_num == -1, we would have
2132   //         checked offsets[17].  The reason for this is that
2133   //         16 and 17 can be in an arbitrary order, since we sort
2134   //         only by offset and last_line_for_offset.  (Note it
2135   //         doesn't help to use line_number as a tertiary sort key,
2136   //         since sometimes we want the -1 to be first and sometimes
2137   //         we want it to be last.)
2138
2139   // This deals with cases (1) and (2).
2140   if ((it == offsets->begin() && offset < it->offset)
2141       || it == offsets->end())
2142     return offsets->end();
2143
2144   // This deals with cases (3) and (4).
2145   if (offset == it->offset)
2146     {
2147       while (it != offsets->end()
2148              && it->offset == offset
2149              && it->line_num == -1)
2150         ++it;
2151       if (it == offsets->end() || it->offset != offset)
2152         return offsets->end();
2153       else
2154         return it;
2155     }
2156
2157   // This handles the first part of case (7) -- we back up to the
2158   // *first* entry that has the offset that's behind us.
2159   gold_assert(it != offsets->begin());
2160   std::vector<Offset_to_lineno_entry>::const_iterator range_end = it;
2161   --it;
2162   const off_t range_value = it->offset;
2163   while (it != offsets->begin() && (it-1)->offset == range_value)
2164     --it;
2165
2166   // This handles cases (5), (6), and (7): if any entry in the
2167   // equal_range [it, range_end) has a line_num != -1, it's a valid
2168   // match.  If not, we're not in a function.  The line number we saw
2169   // last for an offset will be sorted first, so it'll get returned if
2170   // it's present.
2171   for (; it != range_end; ++it)
2172     if (it->line_num != -1)
2173       return it;
2174   return offsets->end();
2175 }
2176
2177 // Returns the canonical filename:lineno for the address passed in.
2178 // If other_lines is not NULL, appends the non-canonical lines
2179 // assigned to the same address.
2180
2181 template<int size, bool big_endian>
2182 std::string
2183 Sized_dwarf_line_info<size, big_endian>::do_addr2line(
2184     unsigned int shndx,
2185     off_t offset,
2186     std::vector<std::string>* other_lines)
2187 {
2188   if (this->data_valid_ == false)
2189     return "";
2190
2191   const std::vector<Offset_to_lineno_entry>* offsets;
2192   // If we do not have reloc information, then our input is a .so or
2193   // some similar data structure where all the information is held in
2194   // the offset.  In that case, we ignore the input shndx.
2195   if (this->input_is_relobj())
2196     offsets = &this->line_number_map_[shndx];
2197   else
2198     offsets = &this->line_number_map_[-1U];
2199   if (offsets->empty())
2200     return "";
2201
2202   typename std::vector<Offset_to_lineno_entry>::const_iterator it
2203       = offset_to_iterator(offsets, offset);
2204   if (it == offsets->end())
2205     return "";
2206
2207   std::string result = this->format_file_lineno(*it);
2208   if (other_lines != NULL)
2209     for (++it; it != offsets->end() && it->offset == offset; ++it)
2210       {
2211         if (it->line_num == -1)
2212           continue;  // The end of a previous function.
2213         other_lines->push_back(this->format_file_lineno(*it));
2214       }
2215   return result;
2216 }
2217
2218 // Convert the file_num + line_num into a string.
2219
2220 template<int size, bool big_endian>
2221 std::string
2222 Sized_dwarf_line_info<size, big_endian>::format_file_lineno(
2223     const Offset_to_lineno_entry& loc) const
2224 {
2225   std::string ret;
2226
2227   gold_assert(loc.header_num < static_cast<int>(this->files_.size()));
2228   gold_assert(loc.file_num
2229               < static_cast<unsigned int>(this->files_[loc.header_num].size()));
2230   const std::pair<int, std::string>& filename_pair
2231       = this->files_[loc.header_num][loc.file_num];
2232   const std::string& filename = filename_pair.second;
2233
2234   gold_assert(loc.header_num < static_cast<int>(this->directories_.size()));
2235   gold_assert(filename_pair.first
2236               < static_cast<int>(this->directories_[loc.header_num].size()));
2237   const std::string& dirname
2238       = this->directories_[loc.header_num][filename_pair.first];
2239
2240   if (!dirname.empty())
2241     {
2242       ret += dirname;
2243       ret += "/";
2244     }
2245   ret += filename;
2246   if (ret.empty())
2247     ret = "(unknown)";
2248
2249   char buffer[64];   // enough to hold a line number
2250   snprintf(buffer, sizeof(buffer), "%d", loc.line_num);
2251   ret += ":";
2252   ret += buffer;
2253
2254   return ret;
2255 }
2256
2257 // Dwarf_line_info routines.
2258
2259 static unsigned int next_generation_count = 0;
2260
2261 struct Addr2line_cache_entry
2262 {
2263   Object* object;
2264   unsigned int shndx;
2265   Dwarf_line_info* dwarf_line_info;
2266   unsigned int generation_count;
2267   unsigned int access_count;
2268
2269   Addr2line_cache_entry(Object* o, unsigned int s, Dwarf_line_info* d)
2270       : object(o), shndx(s), dwarf_line_info(d),
2271         generation_count(next_generation_count), access_count(0)
2272   {
2273     if (next_generation_count < (1U << 31))
2274       ++next_generation_count;
2275   }
2276 };
2277 // We expect this cache to be small, so don't bother with a hashtable
2278 // or priority queue or anything: just use a simple vector.
2279 static std::vector<Addr2line_cache_entry> addr2line_cache;
2280
2281 std::string
2282 Dwarf_line_info::one_addr2line(Object* object,
2283                                unsigned int shndx, off_t offset,
2284                                size_t cache_size,
2285                                std::vector<std::string>* other_lines)
2286 {
2287   Dwarf_line_info* lineinfo = NULL;
2288   std::vector<Addr2line_cache_entry>::iterator it;
2289
2290   // First, check the cache.  If we hit, update the counts.
2291   for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it)
2292     {
2293       if (it->object == object && it->shndx == shndx)
2294         {
2295           lineinfo = it->dwarf_line_info;
2296           it->generation_count = next_generation_count;
2297           // We cap generation_count at 2^31 -1 to avoid overflow.
2298           if (next_generation_count < (1U << 31))
2299             ++next_generation_count;
2300           // We cap access_count at 31 so 2^access_count doesn't overflow
2301           if (it->access_count < 31)
2302             ++it->access_count;
2303           break;
2304         }
2305     }
2306
2307   // If we don't hit the cache, create a new object and insert into the
2308   // cache.
2309   if (lineinfo == NULL)
2310   {
2311     switch (parameters->size_and_endianness())
2312       {
2313 #ifdef HAVE_TARGET_32_LITTLE
2314         case Parameters::TARGET_32_LITTLE:
2315           lineinfo = new Sized_dwarf_line_info<32, false>(object, shndx); break;
2316 #endif
2317 #ifdef HAVE_TARGET_32_BIG
2318         case Parameters::TARGET_32_BIG:
2319           lineinfo = new Sized_dwarf_line_info<32, true>(object, shndx); break;
2320 #endif
2321 #ifdef HAVE_TARGET_64_LITTLE
2322         case Parameters::TARGET_64_LITTLE:
2323           lineinfo = new Sized_dwarf_line_info<64, false>(object, shndx); break;
2324 #endif
2325 #ifdef HAVE_TARGET_64_BIG
2326         case Parameters::TARGET_64_BIG:
2327           lineinfo = new Sized_dwarf_line_info<64, true>(object, shndx); break;
2328 #endif
2329         default:
2330           gold_unreachable();
2331       }
2332     addr2line_cache.push_back(Addr2line_cache_entry(object, shndx, lineinfo));
2333   }
2334
2335   // Now that we have our object, figure out the answer
2336   std::string retval = lineinfo->addr2line(shndx, offset, other_lines);
2337
2338   // Finally, if our cache has grown too big, delete old objects.  We
2339   // assume the common (probably only) case is deleting only one object.
2340   // We use a pretty simple scheme to evict: function of LRU and MFU.
2341   while (addr2line_cache.size() > cache_size)
2342     {
2343       unsigned int lowest_score = ~0U;
2344       std::vector<Addr2line_cache_entry>::iterator lowest
2345           = addr2line_cache.end();
2346       for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it)
2347         {
2348           const unsigned int score = (it->generation_count
2349                                       + (1U << it->access_count));
2350           if (score < lowest_score)
2351             {
2352               lowest_score = score;
2353               lowest = it;
2354             }
2355         }
2356       if (lowest != addr2line_cache.end())
2357         {
2358           delete lowest->dwarf_line_info;
2359           addr2line_cache.erase(lowest);
2360         }
2361     }
2362
2363   return retval;
2364 }
2365
2366 void
2367 Dwarf_line_info::clear_addr2line_cache()
2368 {
2369   for (std::vector<Addr2line_cache_entry>::iterator it = addr2line_cache.begin();
2370        it != addr2line_cache.end();
2371        ++it)
2372     delete it->dwarf_line_info;
2373   addr2line_cache.clear();
2374 }
2375
2376 #ifdef HAVE_TARGET_32_LITTLE
2377 template
2378 class Sized_dwarf_line_info<32, false>;
2379 #endif
2380
2381 #ifdef HAVE_TARGET_32_BIG
2382 template
2383 class Sized_dwarf_line_info<32, true>;
2384 #endif
2385
2386 #ifdef HAVE_TARGET_64_LITTLE
2387 template
2388 class Sized_dwarf_line_info<64, false>;
2389 #endif
2390
2391 #ifdef HAVE_TARGET_64_BIG
2392 template
2393 class Sized_dwarf_line_info<64, true>;
2394 #endif
2395
2396 } // End namespace gold.